Following the 1932 merger, the Cobb County town of Roswell was also ceded to Fulton four months later on May 9, 1932. The cession of Roswell (including everything east of Willeo Creek) made the new county more contiguous, though a very narrow strip (what is now the Dunwoody Panhandle of Sandy Springs, ceded to Milton from DeKalb) actually already connected the two sections.

In 1900, there were several other post offices besides Alpharetta: Arnold, Coker, Dinsmore, Field's Cross Roads, Freemansville, McClure, Mazeppa, Ocee, Skelton, Stono, and Warsaw. Milton totaled or 94,080 acres. There was a population of 6,763, which was 555 more than at the previous (1890) census. Alpharetta had 310 residents, 1,529 lived in and around it. Methodists and Baptists were the dominant religious denominations.